Dawkins is wrong here. He is correct in that sexual jealousy is stupid, but he is missing the point. When someone gives his or her word to another person, he or she must keep that word. This is what cheating is about. If one is in a "open marriage" then one can have sex with any one wants without lying then it is not cheating. When a man marries a women (any relationship for that matter)and swears to the women that he would not have sex with someone else than he needs to follow up on it. Its that simple. I am anti-marriage and anti-monogamy because most people can't keep their vows. But if two people feel that the best way to express their love is through monogamy than more power to them. Cheating is about lying. Love is about sacrifice. If the sacrifice is no sex with third parties than so be it. Dawkins needs to think more poetically and less scientifically when it comes to love.